Process of producing a textile product



Patented Sept. 16, 1952 rnocEss or PRODUCING A TEXTILE PRODUCT,

Ralph James Mann vand JozefBiedawslri, Sponi I don, near Derby, England, assignors to British 1 i a corporation of Great ICelanese' Limited, Br a n, 1

e N Drawing.

Application November 17, 1949, Se-

rial No.- 127,996, In Great BritainDecember This invention relates to improvements the 1 i semi rs, (c te -73) production of sheet materials andis,[more particularly, concerned with the productionof insulating materials comprising fibrous substances in sheetform. M I 7 Prior United Kingdom "Patent No. 582,006'01? British Celanese Limited describes andelaims a process for the production'of batting'having a basis of staple fibres; the process comprising forming alayer of interlaced and matted staple'jfibres, of which a substantial proportion are thermoplastic, and forming a skinon'both sides of said layer by causing the thermoplastic fibres at or near the surfaces of the'jlayer to become adhesiveand to stick to one another solely by the action of heat andpressu're and/or of a'solvent or softening agent for the material of which the thermoplastic fibres consist, while leaving unaffected the thermoplastic fibres in the body of the layer; This process enables insulating materials, useful particularly for heat and' sound insulation purposes, which are of a self support'- ing structure to be obtained in quite'a satisfactory manner. The process"describ'edfhowever,

in which heat is applied to-the thermoplastic fibres by contact with'a heating'surface'does necessitate very careful control of the application of heat a'ndipressure ',or, where this is used,- of

the solvent,andithis'control is di-flicult to obtain where it isid'es'ired 'toformonly a er-y thinskin on the fibrousmaterials- 1 Accordingto"thepresent inve' -tion,;a skin-is formed on a 'massiotfibrous material comprising a substantial' proportion ofthermoplastic fibres by exposinglthe -.'mass of :fibrous materiali 'to radiant heat'and t'erminating the exposure when the fibres fhave -:been V rendered'adhesive' thereby to thetdesired depth inv themass. It has been found that its possible in this way 'to form a v skin upon the .mass of fibrousmaterial and that itis; possible so to control.-:theradiant'heat'. as to produce, if desired; only anexceedingly thin skin Iongthe materials, .so'. thin "indeed as .to produce very.; little: effect uponithe appearanceof the materials. Theprocess of the invention may be employed to produce, successively or'simultaneously, skins'on both sides of -a batting. ;In thiswway products can be obtained which: can be cutiinto -pieces of any desired shape without showing signs of disintegration. Such a product is useful not only for heat and sound insulation but also in, making shoulder pads and'similar articles for useinwearingapparel. in forming ,the skin on'the batting; of heat applied to the surface of the materials the amount by controlling the temperature. of the. radiating surface and also by choice of a suitable distance between theradiating surface and the material being heated. In addition, the time during which heatingisa'pplied naturally, has a substantial effect upon the result obtained Inpractice it .has'beenfound that the application of too much heat tends'to produce shrinkage of the surface fibres, while still 'morei intensive heatingv results in' the production of, fusedlumps of the thermoplastic material. According to animportant feature of the invention, the fibrous material issubje'ct'ed to the action of radiant heat while it is held underfslight'pressure'by a'metal gauze through which-the radiant heat is applied; The action of the metal gauze appears to be such as to prevent the shrinkage of the surface fibres so that a sufficient fusion of these fibres can take place to produce a satisfactory skin without co'ckling of the material 'or theproduction of fused lumps of thermoplastic material. Preferably the gauze used is of q uite thin wire, ,e. g of less than 20 mils diametenjand, of small mesh; e. ginore than 20 meshesper inch. Gauze'ofBO to 40 meshes per inch made from wire of 8 to 10 mils diameter has given excellent results. a g

Better results are sometimes obtained by applying the radiant heat for a number of short periods separated by cooling periods than is the case if the material is merely' maintained for an uninterrupted period under the influence of the radiant heat until a surface skin is formed.

' -In carrying out'the process of the invention, a layer of interlaced and matted staple fibres, of a which a substantial proportion are thermoplastic,:is first formed and thensubjected, as a continuous sheetoras separate lengths of the material, tothe action of radiant heat-until a suitable skin' has been produced. In such a proc- 'ess separate lengthsof the material may be exposednto a radiant heating unit of suitable area or the material, in, separate lengths or as a continuous sheet, may be passed continuously beneath' a radiant heating unit one or moretimes or .su'cces'sivelybeneath a number of such units spaced apart; Surface combustion plates capable of beingheatefd to a temperature of about 900 0., say from 750 to 950 C., have been found to be generally useful for the purposes of the invention. Electrical radiant heating devices may, however, be employed -Thetime during which the material is exposed; to such a heating unit depends, .of :course, uponthe melting point of the thermoplastic fibres used and the distance from the heating unit at which the material is heated. Generally it is preferred to use a short heating period close to the heating unit, rather than a longer heating period at a greater distance. g

Cellulose acetate fibres are in ready supply and the invention is, therefore, of particular importance as applied to materials in which the thermoplastic content consists of these fibres- With cellulose acetate fibres a satisfactory thin skin is formed by a surface combustion plate at about 900 C. situated about? inches from the material using a heating time of littlen ore than one second, e. g. one to one and a half seconds, and repeating this treatment 2 to 4 times, for insta c y passa e at a suitable soeed beneath 2 to 4 such plates, or by passage 2 to 4 times be neath a single plate. If desired, however, a longer heating time may be used, e. g. 5 or seconds per passage to a total of, say, one minute, oreven a total heating time of .2 or more minutes, especially where a'thiclr'er skin is required. In these cases, however, it desirable to operate at a greater distance from the heating unit, e g. 3, 4, 5 ormore inches therefrom, si b v indicated t e P ce s o th in enon s of p r cu ar.imp a efascapriied to the treatment or] fibrous materials in which the her oplast c fib es r mad oi cellul s a we er. t ermop sti fib esot er hsn e ose ace ate may e emp oyed fo exam fi e o other o lui o este e ,slu os Pr on andmix ste s. h as cel ulose ace a p i- Qoo e: and cellul seeootate ut ra e, ce u he s uch as ethy cellulose aodbenzyl ce l lose, synthetic linear polyamide condensation products, polymeric vinyl halides or vinyl esters of organic aeid s,'cqpo1yrners of such yinyl esters d y ho esrpolyme ise methaer acid esters and the like. Th fibrous material treated may ccnsijstwholly of thermoplasticfibres or a n a fib os' i h a en herm p i for instance fibres-of cotton, silk, wool, regenerated cellulose, jute and hemp. Such nonthermoplastic fibres,'if employed, preferably constitute only a small proportion, about 20% or less, of the total'fibr'es, 1

The following example illustrates the process of the invention Example A batting eonsisting o a loosemess of interaced cellulose acetate fibres is passed, while lightly compressed by awire gauze of 3&1 mesh constructed from wire'of .9 mils diameter, ben a h a su ssion-of four eembust n plates; the radiant surfaces of, ion are. situated v2 inches iron the wire gauze and heated to abou 96,0 C, .The plates, whi extend across the Wi th 01ft o batting, are each. about a .foot lon and are separated from each-other by a distance of about .2 feet. battin 'is thus exposed to four heating periods or. about 1 /2 seconds each interrupted by cooling periods of about 3 seconds each,

- The product has-a. :thinxooherent and uniform skin upon its surface. subsequent or si-multane ous formation in. the same way of a skin on the other side of- .the. batting produces a product which n be o t into piec s of any desired shape wi h- 11 showing any signs of: disintegration.

Having described our invention,- what we desire o secure by Letters Patent, is:

' .1, Method of forming a skin on a mass of fibrous material. comprisingv a substantial pro- 4 portion of thermoplastic fibres, which comprises slightly compressing the mass, the pressure on at least one of the faces of the mass being applied along intersecting closely spaced lines, and applying radiaritjheat uporijthe exposed parts of said face betwe'en said intersecting" portions for a period sufiicient to cause a layer of the thermoplastic fibers to become adhesive, terminating said exposure before the inner fibres become adhesive, allowing the exposed fibres to cool sufiiciently to set and afterward removing the pressure. I

2;,M8thod of, ;f,orming a skin on a mass of fibrous material comprising a substantial proportion of thermoplastic fibres, which comprises slightly compressing the mass, the pressure on at least one oifthe'faces of the mass being applied along intersecting portions each less than 20 mils in width and spaced with a greater frequency than 20 per inch, and applying radiant heat upon the exposed pa ts oi said face between aid interseotingportions for a period sufiieientto cause a layer or the thermoplastic fibres to become adhesiv terminatin said exposure before the inner fibres become adhesive, allowing the exposed fibres to cool ufficiently to set and afterwards removing the pressure.

Method of forminsa ski o a s of fibrous materia comprisi g. a bsta ti l p portion of thermoplastic fibers, which mpri s sl ghtly compressing-the mass. th p sure on at leas one of faces of the mass bein applied along intersecting portions each; 8 to 10 mils in Width an pa d w th a frequency of 30 to 40 per inch, and applying radiant heat upon the exposed parts, of said race between said intersectins portions for. a period suffic ent to cause a layer of the thermoplastic fibers to become adhesive, e mi ating said exposure before the inner fibres ee me adhesiv ,.ol.lowinsthe exp fibr s to cool suffici ntly toset and afterwards removing the pressure- .,1Meth dof forming a skin on a'mass of fibrous material comprising a. substantial proportion of thermoplastic: fibres, which comprises slightly eolnpressing the mass, the pressure on at least one ofithe faces of, the mass being appl ed along-intersecting portions. each 8 to 10 mils in widthand spaced with a frequency of 30 to 40 per inch, and applying radiant heat upon the exposed parts of said face. between said int rseot ns. portions tor a succession. of, short periods so. as toscause a layer ofthe thermoplastic fibres tobecome adhesive, terminating said ex-.

'5. Method of forming a slgin on a mass of fibrous material comprising a substantial proportion .of cellulose acetate fibres, which comprises slightly compressing the mass, the pressure on at least one .of the faces of the mass being applied along intersecting .closely spaced lines, and applying radiant heat'upon the exposed parts of" said face between said intersecting portions for a period sufilcient to cause a layer of the cellulose acetate fibres'to become adhesive, terminating said exposure before the inner fibres become adhesive, allowing the exposed fibres to cool sufilciently to set'and afterwards removing the pressure;

6; Method'offorming a skin on a mass of fibrous material comprising a substantial pro-.

posure before the inner fibres become adhesive,

allowing the exposed fibres to cool sufficiently to set and afterwards removing the pressure.

7. Method of forming a skin on a mass of fibrous material comprising a substantial proportion of cellulose acetate fibres, which comprises slightly compressing the mass, the pressure on at least one of the faces of the mass being applied along intersecting portions each 8 to 10 mils in width and spaced with a frequency of 30 to 40 per inch, and applying radiant heat upon the exposed parts of said face between said intersecting portions for a period suificient to cause a layer of the cellulose'acetate fibres to become adhesive, terminating said exposure before the inner fibres become adhesive, allowing the exposed fibres to cool sufficiently to set and afterwards removing the pressure.

8. Method of forming a skin on a mass of fibrous material comprising a substantial proportion of cellulose acetate fibres, which comprises slightly compressing the mass, the pres- 6 sure on at least one of the faces of the mass being applied along intersecting portions each 8 to 10 mils in width and spaced with a frequency of 30 to 40 per inch, and applying radiant heat upon the exposed parts of said face between said intersecting portions for a succession of short periods so as to cause a layer of the cellulose acetate fibres to become adhesive, terminating said exposure before the inner fibres become adhesive, allowing the exposed fibres to cool sufficiently to set and afterwards removing the pressure.

RhLPI-I JAMES MANN.

J OZEI? BIEDAWSKI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,417,453 Wade Mar. 18, 1947 2,433,965 Upson Jan. 6, 1948 2,483,404 Francis Oct. 4, 1949 2,497,117 Dreyfus Feb. 14, 1950 2,544,797 Lippman Mar. 13, 1951 FOREIGN PATENTS Number Country Date 582,006 Great Britain Nov. 1, 1946 

3. METHOD OF FORMING A SKIN ON A MASS OF FIBROUS MATERIAL COMPRISING A SUBSTANTIAL PROPORTION OF THERMOPLASTIC FIBERS, WHICH COMPRISES SLIGHTLY COMPRESSING THE MASS, THE PRESSURE ON AT LEAST ONE OF THE FACES OF THE MASS BEING APPLIED ALONG INTERSECTING PORTIONS EACH 8 TO 10 MILS IN WIDTH AND SPACED WITH A FREQUENCY OF 30 TO 40 PER INCH, AND APPLYING RADIANT HEAT UPON THE EXPOSED PARTS OF SAID FACE BETWEEN SAID INTERSECTING PORTIONS FOR A PERIOD SUFFICIENT TO CUASE A LAYER OF THE THERMOPLASTIC FIBERS TO BECOME ADHESIVE TERMINATING SAID EXPOSURE BEFORE THE INNER FIBRES BECOME ADHESIVE, ALLOWING THE EXPOSED FIBRES TO COOL SUFFICIENTLY TO SET AND AFTERWARDS REMOVING THE PRESSURE. 